Duct booster



L. OY

TER

R. H. M0

DUCT B Jan. TL 1950 3 Sheets-Sheet l Filed Jan. 9, 1947 Jan. 17, 1950 R. H. MQELROY 2,494,772

DUCT BOOSTER Filed Jan. 9, 1947 3 sheets-sheet 2 l la I4 INVENTOR ROY H M cELROY Bmfm ATTORNEYS Jan. 17, 1950 R, H. MCELROY 2,494,772

DUCT BOOSTER l Filed Jan. 9, 1947 3 Sheets-Sheet 5 Flc-:5

INVENTOR ROY H. MCELROY r ATTORNEYS Patented Jan. 17, 1950 UNITED STATES PATENT orifice DUCT BOOSTER Roy H. McElroy, Dayton, Ohio? assignor to International Engineering, Inc., Dayton, h10, a corporation of Ohio This invention relates to a gas circulating unit, and particularly relates to a circulating ian that isadapted tobe placed in an air duct' for boosting the `movement of air or gas through the duct.

An object of lthe invention is to `provide a duct fan or gas circulating unit wherein the prime mover for the fan is located in a housing to prevent contact of gases being handled by the fan with the primemover, and wherein gases exteriorlyoi the duct in .which the fan `and prime mover is mounted `are conducted through the prime mover" exhausted into the duct for cooling the prime mover.

Still another object of the inventionis to provide aduct ian. in accordance with the foregoing object wherein the ifandisposed within the duct for moving the gas ow through the duct produces a movement of` cooling; gas through the prime mover.` u u Another objectofthe invention is to provide a ductfan in accordance with theforegcing objects whereinan.` auxiliary fan is disposedin` operative relationship `with-the prime mover for aiding `in the movement of cooling gas through the prime mover.

Still anotherv object of the invention is to provide a `duct `fan in accordance with any of the foregoingobjectswherein the prime mover consistsof an` electric n motor having air passages throughmthmotor tolall'owior passage of cool` ingvgasesthrough the'smotor, and also wherein the auxiliary fanisdisposedl within the motor for aidingthe `movement"for cooling gas through the moton l n s Further objects` and `advantages will become apparent` from" the drawings andthe following description.-`

In the drawings:

Figure 1 isa perspective elevational view with aportiono'f the Japparatusbroken awayto show the inventionmore clearly and illustrating the use of a ductfan ofthis `invention `within a` duct through which 1 gases pass.`

Figure `2Y is a vertical cross-sectional view taken transversely of the duct in frantoi the ductfan and substantial-lyon line 2-*2 of Figure l.

Figure 3 is` a horizontal crossesectional- View teiten transversely of the ductsubstantially along 3"-53 `ofl'f'igure "1.1

Fig re 4 is averticall cross-sectionai view` taken tra versa-y of the duct iiiust'ranug the weil in W''riicli"A the `prime mover is' located and is taken suhstantialiy aionglinedLl-cfof Figure 1.

Figure-5 is e vertical.crosstseeuonai viewtake longitudinally of the duct substantially along line 5-5 of Figure 1.

Figure 6` is an end view of the motor talien along line 6--6 of Figure 5i Figure 7 is a vertical cross-sectional view `of the opposite end of the motor taken along line 'l-g-ml of Figure 5.

This invention relates to air circulatingrunits or fans that are adapted to be placed within a duct for causing movement `of-` gas through the duct. To provide for economy `oimanufacture of the unitthe fans are usuallycarried directly on the end of the drive shaftof an electricl motor, which motor and fan is installed Within the duct for circulating gas through the duct. However, many times the gases circulated through the duct are harmful to an electric motor,u and at `other times the gases are at a quite high temperature. For these and other reasons it is therefore desir--` able that the prime mover or electric motor shall be positioned within the duct butoutof contact with the gases passing throughthe duct and shall be cooled by movement oi air or gases iro-mvoutside the duct. Y

Duct fans, of the general type just referred are usually installed within a housing that can be connected into and become a part of the duct system carrying the gases. Various proposals have been made and various arrangements used for cooling the primemover of a duct fan which have met with various degrees of success. In this invention however the cooling gas for the prime mover, which as disclosed in this invention is an electric motor, is conducted through the prime mover primarily by the main duct fan which may be aided by an auxiliary fan in or adjacent to the prime `mover -for the purpose of removing the heat of the prime mover and for preventing overheating of it when high temperature gases are handled by the duct fan. I

Inthis invention the air or gas circulating unit I0 isconnected into and becomes a pai-trof the duct Il for movinggases through the duct.

The air circulating unit l0 consists of a housing I2 that is provided with flanged ends I3 andllll adapted to be secured to the duct Il in anysuitable fashion. The housing l2 is provided with; a well I5 that extends radially inwardly Ifrom the periphery of the housing l0.

The well I5 is suitably secured to the periphery of the housing l0 and has the upper end I6 thereof openfor admission of air exteriorly of the housing l0 into the well l5. Normally, the opening I6 oi the well l5 receives air from the roomuatmosphere through` which the duct I`| passes. The well I is provided with a supporting plate I 'I which is adapted to support the prime mover or electric motor I8.

The prime mover or electric motor I8 is introduced into the well I5 through the opening I6 and one end of the motor I 8 is secured to the supporting plate I'I by means of bolts I 9. It will thus be seen that when the motor I8 is placed in the well I5 and secured to the plate I'I that the motor is completely enclosed and separated from the ini terior of the housing I2 so that gases conducted through the housing I2 cannot contact the motor The drive shaft of the motor I8 extends forwardly of the mounting plate I'I and has a main duct fan 2I secured thereon. This fan 2l causes movement of gases through the housing I2 and through the duct I I connected at opposite ends of the housing I 2.

y The electric motor I8 is provided with a cylindrical housingv 22 that carries the stator of the motor in conventional manner and has the end bells 23 and 24 secured to the member 22, also in conventional manner. The end bells 23 and 24 are provided with bearings 25 and 26 respectively which carry the drive shaft 20, the drive shaft 20 extending forwardly of the end bell 24 to carry the fan 2 I v f The end bell 23 of the motor I 8 is provided with a plurality of openings that are positioned in the end bell radially outwardly of the bearing 25 for the shaft 20. These openings 30 allow gas to pass into the interior of the motor I8.

As illustrated in Figure 7 the end bell 24 of the motor I8 is provided with similar openings 3l that are positioned radially outwardly of the bearing 26 which carries the shaft 2G. These openings 3I in the end bell or wall 24 of the motor I8 are therefore positioned just rearwardly of the fan 2I.

The fan 2| driven bythe motor I8 causes movement of air through the housing I2 and around the well I5 in the direction of the arrows indicated in Figures l, 3 and 5. Therefore, the low pressure side of the fan 2| is on the right hand side thereof, as viewed in Figures 3 and 5 and the high pressure side of the fan is on the left hand side thereof.

As is well-known in the conventional construc- 'tion of electric motors, the rotor of the electric motor is spaced from the stator and 'the internal construction generally is such that gas or air can pass internally through the motor. Thus, with :the end bells or walls 23 and 2l! of the motor I8 vprovided with the openings 3U and 3l previously described it will be seen that air or gas can pass Acompletely through the motor I8. With the low pressure side of the fan 2I being adjacent the 'end wall 24 of the motor I8, air will be drawn through the motor I8 by the fan 2l, the air admitted into the motor being received from within the well I5. The well I5 receives its air through the opening I6 which in turn is supplied from the atmosphere around the housing I2 and the duct II. Therefore, cooling gas will be circulated through the motor i8 by means of the main duct fan 2l, this fan drawing the cooling 'gas or air from the well I5 through the openings 38 and 3l in the end walls 23 and 24 respectively of the motor I8. The cooling air passing internally through the motor I8 provides for more satisfactory -cooling of the motor because of the intimate contact of the air with the motor at nthe source of heat therein. Also, since the air circulated through the m-otor I8 is drawn from the well I5 it will be appreciated that the general movement of air through the well I5 will produce external cooling of the motor in addition to the aforementioned internal cooling.

It may be desirable to supplement the movement of air through the motor I8 as caused by the main duct fan 2|, particularly under conditions wherein the duct fan is handling gas at relatively high temperatures. The main duct fan 2I can therefore be supplemented by the use of a fan 35 carried on the motor shaft 20 and positioned internally of the motor I8 at either end of the motor. Also, it will be appreciated that the fan 35 could be mounted upon an extension of the shaft 26 externally of the motor, such as at the right hand end of the motor, see Figure 5. The auxiliary fan 35 would therefore increase the quantity of air delivered through the motor I8 for cooling the same.

vFrom the foregoing description it will be seen that the well I5 completely encloses the motor I8 and yet a highly efficient system is provided for delivering cooling gases through the motor by means of the main duct fan which can be supplemented by means of an auxiliary fan. The well I5 may have plates 36 extending between the Well and the periphery of the housing I2 to more rigidly support the well Within the housing.-

While the apparatus disclosed and described herein constitutes a preferred form of the invention, yet it will be understood that it is capable of modication, and that all modifications of the apparatus that fall within the scope of the appended claims are intended to be included herein.

Having thus fully described my invention, what I claim as new and desire to secure by Letters Patent is:

1. A gas circulating unit comprising, a, housing through which gases may be conducted,- a fan in the housing for moving gases through said housing, an enclosure within said housing on the low pressure side of said fan, means connecting the interior of said enclosure with the exterior of said housing whereby gases exteriorly of the housing can enter said enclosure, a motor Within said enclosure and forming therewith a part of the -wall of the enclosure adjacent said fan on the low pressure side thereof, said motor having the drive shaft thereof extending through said wall into the housing and carrying said fan, and passage means in said motor through which gas from said enclosure can be circulated, said passage means terminating in the wall of said motor that forms a part of the wall of said enclosure adjacent said fan on the low pressure side thereof whereby said fan draws gases through the housing and through said motor and said wall from said enclosure.

2. A gas circulating unit comprising a housing through which gases may he conducted, a fan in the housing for moving gases through said housing, an enclosure within said housing on the low pressure side of said fan and having an opening in a wall thereof adjacent said fan, means connecting the interior of said enclosure with the exterior of said housing Iwhereby gases exteriorly of the housing can enter said enclosure, a motor within said enclosure having one end thereof closing said opening and forming a part of the Wall of the enclosure adjacent said ian on the low pressure side thereof, said motor having the drive shaft thereof extending through said. end into the housing and carrying said fan, and passage means in said motor through which gas from said enclosure can circulate, said passage means terminating in said end of said motor and within the area of Said opening whereby said fan draws gases through the housing and through said motor and said wall from said enclosure.

3. A gas circulating unit comprising a housing through which gases may be conducted, a fan in the housing for moving gases through said housing, an enclosure within said housing on the low pressure side of said fan and having an opening in a Wall thereof adjacent said fan, means lconnecting the interior of said enclosure with the exterior of said housing whereby gases exteriorly of the housing can enter said enclosure, a motor within said enclosure having one end there-of closing said opening and forming a part of the wall of the enclosure adjacent said fan on the low pressure side thereof, said motor having the ldrive shaft thereof extending through said end into the housing and carrying said fan, passage means in said motor through which gas from said enclosure can circulate, said passage means terminating in said end of said motor and within the area of said opening whereby said fan draws gases through the housing and through said motor and said wall from said enclosure, and a booster fan in sai-d motor to boost gas movement through said motor.

ROY H. MCELROY.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 2,223,847 Engdahl Dec. 3, 1940 2,321,126 Breuer June 8, 1943 2,397,170 Jenkins Mar. 26, 1946 2,397,171 Troller et al Mar. 26, 1946 2,419,962 McLarty May 6, 1947 FOREIGN PATENTS Number Country Date 229,708 Great Britain Mar. 26, 1925 

